FEBRUARY HIGHLIGHTS

*note: for the full suite of HAB taxa sampled weekly, see the SCCOOS and CeNCOOS HABMAP database and the Imaging FlowCytobot Dashboard.

Pseudo-nitzschia -

* Important update to C-HARM in this bulletin. C-HARM version 3 is now operational at NOAA CoastWatch. Major changes include: new operational circulation model (WCOFS) for currents, salinity, and temperature and VIIRS ocean color products in place of MODIS Aqua. WCOFS is a 4DVAR data assimilative model run at NOAA Coast Survey Development Lab (CSDL). NOTE: There are serious issues with WCOFS salinity accuracy that have notable consequences for the Particulate Domoic Acid predictions; we will address the impact this has on pDA accuracy in these bulletins. Sensitivity analyses suggest that the impact of the shift to VIIRS for the ocean color inputs to C-HARM is small relative to the replacement of CA ROMS Classic with WCOFS (for salinity).

• • C-HARM tells us where conditions are suitable for species of the diatom Pseudo-nitzschia spp. (all size classes) to grow well and where they might be more likely to produce the deadly neurotoxin, domoic acid (DA). Three independent models are run daily to produce nowcasts and three-day forecasts of the probability of a bloom, the probability of a DA event for particulate DA only, and the probability of a DA event for the cellular portion of DA only. Here, in the bulletin, we summarize nowcasts for the month.
  • C-HARM predictions for Pseudo-nitzschia spp. blooms in February contain quite a lot of pixelation from VIIRS. Bloom potential is extremely high throughout the month, covering much of the California Current. An emphasis on higher risk in northern California emerges throughout the month as well as the Santa Barbara Channel and the Southern California Bight overall. The predictions for Pseudo-nitzschia corroborate something we've seen for a while in the California Current, which is that conditions are fairly regularly conducive to supporting Pseudo-nitzschia populations in most coastal zones.  
  • HABMAP weekly pier sampling in February indicates quite a lot of bloom potential for Pseudo-nitzschia spp. in southern California and the Santa Barbara Channel, but not so much in central or northern California according to the sparse sampling in that region. Both size classes bloomed at Stearns Wharf in Santa Barbara throughout February, and the larger more toxigenic size class exceeded bloom levels at Santa Monica Pier at the end of February. Levels of both size classes were quite high at Newport Beach Pier and Scripps Pier and appeared to be increasing in unison in response to similar environmental forcing.
  • Pseudo-nitzschia activity from CDPH coastal sampling is consistent with a focus on southern California in February. 'Common' densities of the more toxigenic size class, Pseudo-nitzschia 'seriata,' were distributed at sites in the Santa Barbara region, LA and Orange County, and further south to La Jolla, and it was considered 'Present' at even more sites throughout the Southern California Bight.
  • A selection of CA Imaging FlowCytobot (IFCB) Network images from the Bodega Marine Laboratory in northern California and from an offshore buoy at Del Mar (San Diego) in February illustrates the amazing latitudinal gradients from north to south that can be seen with this technology, as it collects images of the phytoplankton community every 30 minutes! Smaller classes of diatoms and some flagellates dominate at the Bodega Marine Lab intake in Horseshoe Cove, while large dinoflagellates and diatoms are more common at Del Mar as the upwelling season develops. 
  • C-HARM probabilities for particulate domoic acid (pDA) and cellular domoic acid (cDA) in February are most intense in central and southern California, and overlap between the two metrics is higher than it was in January. This may be a good indicator that pDA is not overestimating pDA event potential in the Bight relative to the classic ROMS version of the C-HARM, or it may indicate that both pDA and cDA risk are overestimated but for different reasons other than the salinity component of the prediction of pDA. One obvious difference is the low chance of cDA risk in northern California relative to that predicted for pDA in February. This lower risk is corroborated by measurements (albeit not too many). The lack of any DA measured at HABMAP pier sites, even in southern California, highlights both the difficulty in predicting DA from Pseudo-nitzschia bloom levels and the potential for mismatch in DA production between nearshore pier sites and offshore locations on the shelf. 
  • Animal strandings from potential DA toxicosis in February are consistent with C-HARM predictions of high DA risk in the Bight and HABMAP observations of bloom levels of the toxigenic size class at southern California pier sites. Two adult female California Sea Lions were recovered by the Marine Mammal Care Center of Los Angeles and by the Pacific Marine Mammal Center in Orange County. 
  • CDPH lifted an advisory on January 9 for mussels, scallops, and most types of clams in Humboldt County due to PSP and ASP. However, the advisory related to sport-harvested razor clams from Humboldt and Del Norte counties seems to remain in effect due to ASP risk. Given the low depuration (detox) rates of razor clams, DA levels in razor clams are usually more a reflection of long-term exposure to DA rather than real-time or recent bloom conditions. However, since this same advisory was lifted in June and then reinstated in November of this year, there has likely been persistent, if low-level, production of DA in the North Coast region. 
    

    Alexandrium -

    • CDPH detected 'Rare' levels of Alexandrium spp. in February at one site in Humboldt Bay where HABMAP does not have a routine sampling site for Alexandrium. The lack of Alexandrium activity is, however, consistent overall with HABMAP, with only one record of detection at one site, Scripps Pier, in the entire month. In line with that, the Paralytic Shellfish Poisoning (PSP) advisory was lifted on January 9 for mussels, scallops, and most types of clams in Humboldt County. 

    Summary written by Clarissa Anderson on 10 April 2023

Pseudo-nitzschia "seriata" was detected at "Common" density levels on 7 occasions:

• 2023-02-13 10% La Jolla, Scripps Pier
• 2023-02-17 10% Santa Barbara, Mohawk Reef
• 2023-02-17 12% Redondo Beach Breakwater
• 2023-02-17 15% Palos Verdes, OFFSHORE
• 2023-02-21 14% La Jolla, Scripps Pier
• 2023-02-21 40% Goleta Pier
• 2023-02-27 21% La Jolla, Scripps Pier

Pseudo-nitzschia "seriata" was detected at "Present" density levels on 8 occasions: 

• 2023-02-06 1% La Jolla, Scripps Pier
• 2023-02-08 1% Goleta Pier
• 2023-02-15 1% Manhattan Beach Pier
• 2023-02-15 2% Pacific Beach Pier
• 2023-02-16 1% Imperial Beach Pier
• 2023-02-16 3% Marina Del Rey
• 2023-02-22 8% Imperial Beach Pier
• 2023-02-24 7% Bolsa Chica

Pseudo-nitzschia "seriata" was detected at "Rare" density levels on 8 occasions:

• 2023-02-01 0.5% Goleta Pier
• 2023-02-02 0.5% Redondo Beach Pier
• 2023-02-03 0.5% Bolsa Chica
• 2023-02-04 0.5% Palos Verdes Rocky Pt Offshore
• 2023-02-06 0.5% Tomales Bay, Lease #M430-15
• 2023-02-08 0.5% Santa Cruz Wharf
• 2023-02-10 0.5% Bolsa Chica
• 2023-02-15 0.5% Crystal Cove SB, OFFSHORE

Alexandrium spp. were detected in 1 of the 72 samples: 

Alexandrium spp. were not detected at "Common" density levels. 

Alexandrium spp. were not detected at "Present" density levels.

Alexandrium spp. were detected at "Rare" density levels once: 

• 2023-02-06 0.5% Humboldt Bay, Indian Is. Ch.